Easy-installer failed on samsung S9

As you say Easy Installer just does it’s thing and does what is required and you do not influence its choices. Follow the link below to check the version of /e/ which Easy Installer will install today; it is Oreo.

But the phone will still boot into Download mode? You might need to catch it as it powers down, and button press for Download mode. Or not?

[LIST] Devices working with the Easy Installer